There has been increasing interest in substances which can function as flavoring agents for modifying or improving the flavor and aroma of foodstuffs, tobaccos, beverages and pharmaceutical preparations.
The role of alkylpyrazines and alkylpyridines as natural flavor constituents in various foodstuffs is well known. This knowledge has stimulated the development of foodstuff formulations containing synthetic alkylpyrazines and alkylpyridines as flavorant additives.
U.S. Pat. No. 3,323,402 discloses pyrazine derivatives corresponding to the formula: ##STR2## wherein X represents a member selected from the group consisting of oxygen and sulfur and one of the symbols R.sub.1, R.sub.2 and R.sub.3 represents a methyl radical, the other two representing hydrogen. This class of pyrazine derivative imparts a flavor and aroma of roasted hazelnuts, peanuts or almonds when incorporated in foodstuffs and beverages as a flavorant additive.
U.S. Pat. No. 3,619,210 describes the use of 2,6-dimethylpyrazine as a flavor enhancer in chocolate preparations. U.S. Pat. No. 3,829,582 discloses that pyrazine derivatives are useful for imparting fatty-fried flavor to potato chips.
More recently, it has been established that alkylpyrazines are natural components of tobacco smoke, and that they most probably are important contributors to tobacco smoke flavor [A. Baggett et al, J. Chromatog, 97, 79 (1974)]. Further, it has been disclosed in the patent literature that addition of alkylpyrazines to tobacco results in an improvement in the flavor of smoking compositions as perceived by a test panel.
British Pat. No. 1,244,068 describes a method for influencing the smoke flavor of tobacco or a tobacco mixture which consists of treating the tobacco with a pyrazine derivative of the following chemical structure: ##STR3## in which each R is independently a hydrogen atom, an aliphatic radical, an alicyclic radical or an aromatic hydrocarbon radical, such radicals having up to 9 carbon atoms, or R is a heterocyclic radical containing 4 to 9 carbon atoms.
U.S. Pat. No. 3,402,051 describes a process for imparting a popcorn-like flavor and aroma to tobacco and foodstuffs by the incorporation of a 2-acetylpyrazine derivative therein.
Other patents which disclose the addition of various pyrazine compounds to tobacco and foodstuffs as a means of providing flavor or flavor enhancement include U.S. Pat. Nos. 3,684,809; 3,705,158; 3,754,934; 3,764,349; 3,767,426; and 3,881,025.
Alkylpyridines have also been found to be useful tobacco additives. As an example, U.S. Pat. No. 3,625,224 describes the use of methylpyridines, ethylpyridines and various dialkylpyridines as tobacco additives. U.S. Pat. No. 3,381,691 discloses 2-methyl-5-isopropylpyridine as a tobacco additive.
It is characteristic of both pyrazine and pyridine derivatives employed as tobacco flavorants in the prior art, as illustrated by the above described technical literature, that the respective heterocyclic derivatives have the disadvantage of both high volatility and low odor threshold. Both of these properties significantly restrict the extent that these heterocyclic derivatives can be utilized as flavorants in tobacco compositions. A quantity of a pyrazine or pyridine derivative in a tobacco composition sufficient to have a noticeable effect in low delivery cigarettes causes a marked pack aroma.
Accordingly, it is a main object of this invention to provide tobacco and non-tobacco smoking compositions which have incorporated therein a substituted pyrazine or pyridine compound as a flavorant additive which is characterized by low volatility and low pack aroma.
It is another object of this invention to provide smoking compositions of tobacco and non-tobacco materials, and blends thereof, containing a substituted-pyrazine and/or substituted-pyridine flavorant additive, which smoking compositions are adapted to impart flavoring to the mainstream and sidestream smoke under smoking conditions.
It is a further object of this invention to provide novel hydroxyethyl-substituted pyrazine and pyridine compounds which can be subjected to pyrolysis conditions to yield constituents which can enhance the flavor and aroma of smoking compositions and foodstuffs.
Other objects and advantages of the present invention shall become apparent from the accompanying description and examples.